My b2evolution Version: Not Entered

I recently upgraded to 4.0.4 and am having some troubles with my dashboard. I was trying to fix an error with the Captcha plugin (no images) and when I clicked on either the 'Reload Plugins' or 'Install New' I am taken to a 404 that says 'no server can be found at admin.php.'

Have I installed something incorrectly?

Thanks.